The present invention relates to a device for detecting the rotation of a spool on a fishing reel and, more particularly, to improvements in a spool revolution sensing device incorporating a magnet and Hall effect devices.
In recent years, a device has been available that can measure and display the length of the paid out portion of a fishing line on a fishing reel, such as a casting reel, while the line is being cast, as well as the length of the wound portion of the line after the line is cast. Such device incorporates a sensor for detecting the revolutions of the spool, a microcomputer for calculating the length of the paid out and/or wound portion from the number of revolutions of tee spool sensed by the sensor, and an LCD display unit for the result of the calculation. Examples of this type of device are disclosed in published Japanese Patent Specification No. 48839/1981 and Japanese Utility Model Application No. 8693/1984, each of which were filed by the present applicant.
In fishing reels incorporating such devices, the sensor for detecting spool revolution is an important component. The sensor disclosed in the aforementioned published Patent Specification No. 48839/1981 comprises a stationarily mounted reed switch and a cooperating magnet carried on a rotatable member. The sensor disclosed in the aforementioned Utility Model Application No. 8693/1984 comprises a magnet carried on the reel spool and fixedly mounted co-acting Hall effect devices.
Usually magnets for activating the reed switch or Hall effect devices are located at a position remote from the axis of rotation of the rotating body, such as a spool. Such magnets are of relatively large size to assure effective contact with the reed switch or Hall effect devices for accurate operation. For these reasons, the circumferential weight distribution of the rotating body is unbalanced, causing the rate of rotation to be nonuniform. This is especially true with a magnet mounted on a spool for use with a casting reel, when the rate of rotation of the spool may reach a frequency of 10,000 rpm, or more, when the fishing line is cast. At the present time, the nonuniform rotation of the spool causes the spool and the body of the reel to vibrate, which may produce audible resonance or abnormal sounds. Further, the distance that can be traveled by the fishing tackle is reduced.
It is a primary object of the present invention to provide a device which senses the revolutions of a spool for use with a fishing reel and wherein the spool will be caused to revolve at a uniform rate. It is another object of the present invention to provide a sensing device of the character stated incorporating a magnet located upon the spool and with means for balancing the weight of the magnet so that the circumferential weight distribution of the spool is balanced and thereby permitting uniform rotation and with avoidance of vibration.
It is another object of the present invention to provide a sensing device of the character stated which may be economically produced; and which is extremely durable and reliable in usage.
The foregoing objects are achieved by a device which senses the revolution of a fishing reel mounted spool wherein the sensor is composed of a magnet mounted on one side of the spool for rotation therewith and cooperating members carried on a stationary section in opposed relation to the magnet, and with the spool being provided with one or more members such that the weight of the magnet is balanced to effect proper weight distribution of the spool in order to produce a uniform rate of rotation during operation, obviating the likelihood of vibrations and audible resonance.